If 12th term of an AP is 12 and the sun of its first four term is 24 what is sum of its first four terms?

If 12th term of an AP is 12 and the sun of its first four term is 24 w

1.	If 12th term of an AP is 12 and the sun of its first four term is 24 what is sum of its first four terms?
Answer» $a12 = a + 11d = 12 ......(1)$ and SUM of first 4 TERMS is 24 $\frac{n}{2} \: (2a + (n - 1)d) = 24 \\ \frac{4}{2} (2a + 3d) = 24 \\ 2a + 3d = 12...(2)$ equation ( 1 ) × 2 2a + 22D = 24.....(3) eq(3) - eq(2) 19d=12 d=12/19 put d in (1)

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If 12th term of an AP is 12 and the sun of its first four term is 24 what is sum of its first four terms?

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